NOAA: Warmest Global Ocean Surface Temperatures on Record for July

August 14, 2009

The planet’s ocean surface temperature was the warmest on record for July, breaking the previous high mark established in 1998 according to an analysis by NOAA’s National Climatic Data Center in Asheville, N.C. The combined average global land and ocean surface temperature for July 2009 ranked fifth-warmest since world-wide records began in 1880.

Global Climate Statistics

The combined global land and ocean surface temperature for July 2009 was the fifth warmest on record, at 1.03 degrees F (0.57 degree C) above the 20th century average of 60.4 degrees F (15.8 degrees C).

The global ocean surface temperature for July 2009 was the warmest on record, 1.06 degrees F (0.59 degree C) above the 20th century average of 61.5 degrees F (16.4 degrees C). This broke the previous July record set in 1998. The July ocean surface temperature departure of 1.06 degrees F from the long-term average equals last month’s value, which was also a record.

The global land surface temperature for July 2009 was 0.92 degree F (0.51 degree C) above the 20th century average of 57.8 degrees F (14.3 degree C), and tied with 2003 as the ninth-warmest July on record.

Notable Developments and Events

Large portions of many continents had substantially warmer-than-average temperatures during July 2009. The greatest departures from the long-term average were evident in Europe, northern Africa, and much of western North America. Broadly, across these regions, temperatures were about 4-7 degrees F (2-4 degrees C) above average.

Cooler-than-average conditions prevailed across southern South America, central Canada, the eastern United States, and parts of western and eastern Asia. The most notably cool conditions occurred across the eastern U.S., central Canada, and southern South America where region-wide temperatures were nearly 4-7 degrees F (2-4 degrees C) below average.

Arctic sea ice covered an average of 3.4 million square miles during July. This is 12.7 percent below the 1979-2000 average extent and the third lowest July sea ice extent on record, behind 2007 and 2006. Antarctic sea ice extent in July was 1.5 percent above the 1979-2000 average. July Arctic sea ice extent has decreased by 6.1 percent per decade since 1979, while July Antarctic sea ice extent has increased by 0.8 percent per decade over the same period.

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